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A microtome which uses a glass or diamond knife, allowing sections of cells to be cut 300 nanometers in thickness.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an instrument for cutting extremely thin sections of tissue for examination under an electron microscope.

The motion of the knife or the tissue is strictly regulated at a specific height in order to obtain sections that are usually not thicker than 200 angstroms (A) and are sometimes about 50 A thick. The thickness of a section depends on the quality of the fixing medium and the sharpness of the cutting edge of the knife. In most ultramicrotomes, the knife does not move, and the tissue is moved mechanically or, most often, thermally. The thermal mechanism, which was proposed in 1953 by F. Sjôstrand, operates on the basis of the controlled thermal expansion of the support rod to which the tissue is attached.

The USSR has developed an ultramicrotome based on the thermal mechanism that furnishes sections with a thickness of 50-800 A. Glass and diamond blades are used in ultramicrotomes. The quality of the blades is checked under a dark-field microscope, where the cutting edge of a blade of sufficient quality appears as a bright straight line.


Elektronnomikroskopicheskie metody issledovaniia biologicheskikh ob”ektov. Moscow, 1963.
Weakley, B. S. Elektronnaia mikroskopiia dlia nachinaiushchikh. Moscow, 1975.
Sjôstrand, F. S. Electron Microscopy of Cells and Tissues, vol. 1. New York-London, 1967.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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The ultrathin sections of sample with the thickness 70-80 um were prepared via ultramicrotomy technique using Reichert Ultramicrotome Supernova.
As the composites are elastomeric in nature, the sample temperature during ultramicrotomy was maintained at -60[degrees]C, which was well below the glass transition temperature ([T.sub.g]) of ENR composites.
Sections with thickness of ~70 nm were obtained from samples via ultramicrotomy at ambient temperature.
The samples for HRTEM analysis were prepared using an ultramicrotomy with a Leica Ultracut UCT (Leica Microsystems GmbH, Vienna, Austria).
Lines or scratches in surfaces, appearing after ultramicrotomy cutting due to the resol fragility, made difficult the observation of individual layers.
The specimens were prepared by ultramicrotomy (Ultracut S from Leica), and some samples were exposed to osmium tetroxide ([O.sub.s][O.sub.4]).
The samples for transmission electron microscopy (TEM) analysis were prepared using an ultramicrotomy with a Leica Ultracut UCT (Leica Mikrosystems GmbH, Vienna, Austria).
Through this analysis it is possible to evaluate particle parameters such as thickness, length, aspect ratio, and interparticle distance, although a more recent study has shown that the image analysis underestimates the length and aspect ratio of the particles, due to effects that arise from the preparation of TEM samples by ultramicrotomy and to projection effects caused by the wavy shape of the clay particles (15).
Samples were prepared by ultramicrotomy at room temperature, giving sections of nearly 100 nm in thickness.